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Main Authors: Sharma, Amis, Chen, Chun-Chia, McCourt, Jordan, Kim, Mingi, Watanabe, Kenji, Taniguchi, Takashi, Rokhinson, Leonid, Finkelstein, Gleb, Borzenets, Ivan
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.10640
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author Sharma, Amis
Chen, Chun-Chia
McCourt, Jordan
Kim, Mingi
Watanabe, Kenji
Taniguchi, Takashi
Rokhinson, Leonid
Finkelstein, Gleb
Borzenets, Ivan
author_facet Sharma, Amis
Chen, Chun-Chia
McCourt, Jordan
Kim, Mingi
Watanabe, Kenji
Taniguchi, Takashi
Rokhinson, Leonid
Finkelstein, Gleb
Borzenets, Ivan
contents We perform transport measurements on proximitized, ballistic, bilayer graphene Josephson junctions (BGJJs) in the intermediate-to-long junction regime ($L>ξ$). We measure the device's differential resistance as a function of bias current and gate voltage for a range of different temperatures. The extracted critical current $I_{C}$ follows an exponential trend with temperature: $ \exp(-k_{B} T/ δE)$. Here $δE = \hbar ν_F /2πL $: an expected trend for intermediate-to-long junctions. From $δE$, we determine the Fermi velocity of the bilayer graphene, which is found to increase with gate voltage. Simultaneously, we show the carrier density dependence of $δE$, which is attributed to the quadratic dispersion of bilayer graphene. This is in contrast to single layer graphene Josephson junctions, where $δE$ and the Fermi velocity are independent of the carrier density. The carrier density dependence in BGJJs allows for additional tuning parameters in graphene-based Josephson Junction devices.
format Preprint
id arxiv_https___arxiv_org_abs_2412_10640
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fermi Velocity Dependent Critical Current in Ballistic Bilayer Graphene Josephson Junctions
Sharma, Amis
Chen, Chun-Chia
McCourt, Jordan
Kim, Mingi
Watanabe, Kenji
Taniguchi, Takashi
Rokhinson, Leonid
Finkelstein, Gleb
Borzenets, Ivan
Mesoscale and Nanoscale Physics
Quantum Physics
We perform transport measurements on proximitized, ballistic, bilayer graphene Josephson junctions (BGJJs) in the intermediate-to-long junction regime ($L>ξ$). We measure the device's differential resistance as a function of bias current and gate voltage for a range of different temperatures. The extracted critical current $I_{C}$ follows an exponential trend with temperature: $ \exp(-k_{B} T/ δE)$. Here $δE = \hbar ν_F /2πL $: an expected trend for intermediate-to-long junctions. From $δE$, we determine the Fermi velocity of the bilayer graphene, which is found to increase with gate voltage. Simultaneously, we show the carrier density dependence of $δE$, which is attributed to the quadratic dispersion of bilayer graphene. This is in contrast to single layer graphene Josephson junctions, where $δE$ and the Fermi velocity are independent of the carrier density. The carrier density dependence in BGJJs allows for additional tuning parameters in graphene-based Josephson Junction devices.
title Fermi Velocity Dependent Critical Current in Ballistic Bilayer Graphene Josephson Junctions
topic Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2412.10640